Coions, in addition to counterions, interact with polyelectrolytes in solution via Debye-Huckel forces. The coion-polyion interaction will be studied experimentally (1) by comparing the specific interaction of the sodium salts of anions of different change with a given polyelectrolyte; (2) by determining the influence of the charge density of polyelectrolyte and of the nature of the pendant charge group on the interactions with coions; and (3) by determining the concentration dependence of the interaction. The experimental techniques to be employed are the capillary method for the self-diffusion of the anion and the emf method utilizing specific ion electrodes. The sodium salts of iota-carrageenan, algin and DNA and of C1 negative, Br negative, I negative, NO3 negative, SO4 negative -2 and Fe(CN)6 -4 will be used. BIBLIOGRAPHIC REFERENCES: F. Tuffile and P. Ander, "Electrical Transport of Ionic Polysaccharides", Macromolecules, 8, 789 (1975). M. Kowblansky and P. Ander, "Interactions of Multivalent Coions and Sodium Ions with Polyelectrolytes by Diffusion Studies", J. Phys. Chem., 80, 297 (1976).